t={[""]=0,["A"]=10}while""do
a,b=io.read():match"(.*) (.*)"s=""y=0
for i=1,4 do
c=a:sub(-i,-i)d=b:sub(-i, -i)x=y+(t[c]or c)+(t[d]or d)y=(x-1)/10
y=math.max(0,y-y%1)x=x-10*y
s=(({"",[11]="A"})[1+x]or x)..s
end
print(s)end